Frequencies for first 10,000 rows of copd variable in nhamcsed2015 dataset : Does | patient | have: | Chronic | obstructive | pulmonary | disease | (COPD) | Freq. Percent Cum. ------------+----------------------------------- No | 9,446 94.46 94.46 Yes | 554 5.54 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 20 Nov 2017